What was found
ON CLIMB OUT, NR 3 ENGINE OIL QUANTITY DECREASED STEADILY TO APPROXIMATELY ONE GALLON. AIR TURNBACK TO BOSTON AND AIRCRAFT LANDED WITHOUT INCIDENT. AIRCRAFT WAS INSPECTED AND SERVICE NR 3 ENGINE OILS. RAN ENGINE ON GROUND AND NO OIL LOSS OR LEAKS WERE NOTED ON GROUND IAW MM 79-31-0. AIRCRAFT RETURNED TO SERVICE. ON CLIMB OUT, NR 3 ENGINE OIL QUANTITY DECREASED STEADILY. AIRCRAFT AIR TURNBACK TO BOSTON AND LANDED WITHOUT INCIDENT. RAN ENGINE PER MM 71-00-67 PAGE 211 AND NOTED EXCESSIVE OIL COMING FROM BREATHER. SUSPECT #5 BEARING CARBON SEAL BAD. PREPARED ENGINE FOR FERRY FLIGHT. REPLACED THE NR 3 ENGINE, LEAK, TRIM AND OPERATIONAL CHECK GOOD PER MM 71-00. AIRCRAFT RETURNED TO SERVICE.